New multimedia geometrical tolerancing course ...

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ScienceDirect Procedia CIRP 10 (2013) 312 – 316

12th CIRP Conference on Computer Aided Tolerancing

New multimedia geometrical tolerancing course Zbigniew Humiennya*, Marcin Bertab a

Institute of Machine Design Fundamentals, Warsaw University of Technology, ul. Narbutta 84, 02-524 Warsaw, Poland b Institute of Metrology and Biomedical Engineering, Warsaw University of Technology, ul. Sw. Andrzeja Boboli 8, 02-525 Warszaw, Poland

Abstract The new application Geometrical Tolerancing developed for usage during lectures at technical universities as well as for the enhancement of vocational trainings for design, manufacturing and metrology engineers working in industry is presented. The application capabilities are shown and discussed on base of the selected screen shoots. The suggestive 3-D animations and multicolour drawings with intuitive user interface are employed to effectively familiarize the application user with definitions of form, orientation, location and run out tolerances. The tolerance zones for toleranced integral or derived features are clearly visualized and then shrunk to show particular deviations. The role of the datums and datum systems for establishing involved tolerance zones is explained in details. The restrictions for the part geometry imposed by specified maximum material requirement or least material requirement that combine requirements for size of the features of size and the geometrical tolerance to one aggregated functional requirement are shown. The concepts of the geometrical deviations evaluation by coordinate measuring techniques or workpiece verification by hard gauges are demonstrated for the selected tolerances with case studies. accessand/or under CC BY-NC-ND license. © 2012 2013 The The Authors. © Authors. Published Published by by Elsevier Elsevier B.V. B.V.Open Selection peer-review under responsibility of Professor Xiangqian Jiang. Selection and peer-review under responsibility of Professor Xiangqian (Jane) Jiang

Keywords: Geometrical tolerancing; Tolerance indication; e-learning; ISO 1101; GPS

1. Introductiona During the last decade the new editions of a few ISO standards addressing fundamentals of geometrical tolerancing issues where published (e.g. ISO 1011:2012; ISO 2692:2006; ISO 5459:2011, ISO 8015:2011, ...) [1, 2]. The majority of definitions and rules given in the series of the ISO standards with common heading Geometrical Product Specification were redefined and clarified. Some new concepts, e.g. RPR – reciprocity requirement were introduced. On the other hand the demands for suppliers, especially in the automotive industry, and wide application of coordinate measuring machines raised the understanding that plus/minus tolerancing is no longer valid because it is ambiguous,

* Corresponding author. Tel.: 0-48-22-234-8577; . E-mail address: [email protected].

fax:+48-22-234-8622

confusing and insufficient for precise definition of allowable departure from the nominal workpiece geometry [3]. The fourteen tolerancing symbols and tolerance frames notation are world wide spread, but author's consultancy given to industry and analysis of the number of the drawings shows that proper understanding is not common. Moreover, the knowledge of default conditions or changes imposed by over ten modifiers or usage of the composite tolerancing concept is rather weak. There is the worldwide need for various kinds of vocational trainings and courses on geometrical dimensioning and tolerancing [4, 5]. The survey over offered seminars shows that they are mainly provided by American experts, so they are focused on geometrical tolerancing interpretation based on ASME Y14.5-2009 (popularly known as Geometrical Dimensioning and Tolerancing), which in many cases is different from approach based on the series of the ISO standards (known as Geometrical Product Specification) [6]. Some

2212-8271 © 2013 The Authors. Published by Elsevier B.V. Open access under CC BY-NC-ND license. Selection and peer-review under responsibility of Professor Xiangqian (Jane) Jiang doi:10.1016/j.procir.2013.08.048

Zbigniew Humienny and Marcin Berta / Procedia CIRP 10 (2013) 312 – 316

Fig. 1. Main window of the application Geometrical Tolerancing

of the seminars are supplemented by educational software based on the ASME standard, but there is lack of the applications that support the ISO approach. So we decided to develop an application that can help to understand the ISO GPS concepts. A few years ago one of the coauthor led the team that developed the program Geometrical tolerances – Definitions and evaluation of deviations [7]. The program, developed in Visual Basic 6, was used and had good reception both in industry as well as among students during lectures. Currently new, more efficient tools for development of multimedia applications with high quality graphic and animations are available. The both have encouraged us to develop a new application. The main features of the application are: clear explanations with static and dynamic 3D drawings of realistic actual parts; advanced multiple frame 3D animations; intuitive user interface; user friendly menu and explanations; potential extensive educational general purpose usage; consistent intuitive colors; tests with dialog boxes; mobility.

2. Structure and main features of the application Geometrical Tolerancing The application Geometrical Tolerancing is developed in the authoring environment Adobe Flash CS5. The main aim for this application is presentation of the specification and interpretation rules for geometrical tolerance symbols that are used to convey functional requirements to the technical product documentation. The learning content is providing the opportunity to make a good presentation and self-studying. The application starts from Main window (Fig. 1) in which the user can click on one from 14 Tolerance symbol buttons, Datums button or any Modifier button to open Case selection window (Fig. 2) with the list of

Fig. 2. Case selection window with listed particular applications of perpendicularity tolerance. Button in the bottom right corner secures return to the Main window

cases of its applications (e.g. perpendicularity of the axis to the plane, perpendicularity of the pin axis with MMR to the plane, perpendicularity of the plane to the plane, perpendicularity of the plane relative to datum system that consists of two planes, etc.). The selection of the particular case by the Line button opens Definition window with the relevant tolerance and the datum frames attached to the workpiece (Fig. 3). There is one template for the Definition window employed in the application, so after a while user can intuitively operate the application. The Definition windows for particular tolerances are used to present key rules for indication the selected case of tolerance as well as to explain how the tolerance zone looks like and how the datum (datum system) constraints the spatial placement of the tolerance zone. The on screen notes and small context popup windows are used to explain requirements defined by the specification. On the right edge of each Definition window pull down menu with four options (Specification, 2D-drawing, 3D-drawing, Interpretation) is available. Selection of the Interpretation button activates the sequence of animations controlled by the user in which she/he is instructed how the datum (or datum system) is established. Next the tolerance zone is presented. The running translation and/or rotation of the tolerance zone clearly shows its unconstraint degrees of freedom (Fig. 4, 5). Finally the user triggers the geometrical deviation evaluation to see the concept of the particular deviation assessment on the extracted (actual) workpiece and can straightforwardly compare the deviation (deviation zone) to the tolerance (tolerance zone). The interpretation of each geometrical tolerance is given by animations supplied by the sequence of a few windows: Actual feature ⇔ Set the datum (+⇔ Set the secondary/tertiary datum, if applicable) ⇔ Show the

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Fig. 3. Definition window with perpendicularity tolerance specification and expanded right edge pull down menu

tolerance zone ⇔ Evaluate the deviation, which can be switched by Forward/Backward buttons that are available in the bottom right corner of each Interpretation window. The prompt line in each interpretation window indicates action that will be released by clicking the Forward/Backward button. For each discussed interpretation the deviations of the considered actual features are exaggerated to make more obvious the datums establishment and deviation assessment. The Fig. 5 contains the last scene of the datum system construction – the application user can clearly recognize that the primary datum is the associated (contacting) plane and the secondary datum is an associated plane that respects the orientation constraint from the primary datum. The ongoing

Fig. 4. Interpretation window – the second from the series of interpretations windows developed for perpendicularity tolerance of the plane relative to the datum system established by two planes. Through the continuous movement of the tolerance zone and the pair of two sided arrows two unconstrained degrees of freedom for the tolerance zone left by established primary datum are shown

Fig. 5. Interpretation window – the third from the series of interpretations windows developed for perpendicularity tolerance of the plane relative to the datum system established by two planes. It is clearly communicated that introduction of the secondary datum leaves only one unconstrained degree of freedom for the perpendicularity tolerance zone. The answer in test box (top right) is still covered. The command Evaluate the deviation displayed in the prompt line indicate the expected action for the next window

movement of the tolerance zone (marked additionally by the two sided arrow) shows that one degree of freedom is left for the perpendicularity tolerance zone.The command displayed in the prompt line (Evaluate the deviation in Fig. 5) informs what will be demonstrated in the next window released by clicking the Forward button. It is expected that after study the information given in each Specification window the user acquire knowledge indispensable for execution of particular geometrical tolerance specification or verification. The empty Test boxes in selected Interpretation windows encourage the user to test her/his knowledge. The click on the Test box button uncovers the right answer that should be compared with the answer given by the user (Fig. 5, 8). The presentation of the maximum material requirement (MMR), least material requirement (LMR) or reciprocity requirement (RPR) also starts from the Definition window (Fig. 6), but next slightly different approach is applied. The effort in animations is put on presentation that the two requirements – size and geometrical tolerance – are combined into one collective requirement. The Definition window with maximum material requirement for internal cylindrical feature based on size and orientation (perpendicularity) requirements is accessible in two ways – from Case selection window for perpendicularity tolerance as well as from Case selection window for maximum material requirement. The MMR, LMR and RPR are presented in the ISO 2692 standard in rigorous way by 14 rules that secure the unambiguity of the requirements definitions, but on the


Fig. 6. Definition window with the maximum material requirement (MMR) for the internal cylindrical feature based on the size and orientation (perpendicularity) requirements

other hand are hard to understand by people that have low experience in geometrical tolerancing. The approach applied in ISO 2692 represents the new concept of the GPS standards development adopted by the Technical Committee ISO/TC 213 Dimensional and Geometrical Product Specifications and Verification [3] – the standards should contain the generalized rules for the geometrical tolerancing and should not be a set of drawings with examples. Some examples of specifications may be given only in an Informative Annex to an International Standard. The terms Maximum Material Virtual Condition (MMVC) or Maximum Material Virtual Size (MMVS) introduced in ISO 2692 are not so obvious for each student. The application Geometrical Tolerancing helps to understand the modifiers concepts. The formula for

Fig. 7. Specification window for the MMR with open popup window that explain how maximum material virtual size (MMVS) is calculated and decodes particular acronyms. The popup window is invoked thanks to the Question mark button

Fig. 8. Interpretation window for the MMR (the fifth from the series of interpretations windows) – the gauge (the pin perpendicular to its base) with maximum material virtual size MMVS = 20,04 mm represents the matting part. The answer in the Test box (bottom middle) for displayed question (Two points size:) is disclosed – user can check whether her/his answer is right

calculation of the MMVS is given in popup windows (Fig. 7) with indication what are the summands of the MMVS. The Interpretation window with animation presenting verification of the MMR (Fig. 8) clearly shows what the meaning of the MMVS is – the introduced envelope called the maximum material virtual condition should not be violated by the workpiece materail. Thanks to the animation the user may easily understand that the application of the maximum material requirement for tolerancing of mating features of size enables unique specification of functional requirements with highest allowable tolerances that output significant technical and economic benefits. Some of the work pieces that are rejected when verified according to the classical tolerancing notation (no modifier applied) may

Fig. 9. Interpretation window for the assembly of the ring with the respective matting pin perpendicular to its base – both elements are toleranced with MMR (see Fig. 6 for the ring)

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be assessed as acceptable when the maximum material requirement is applied. This due to the fact that priority is given to the parts assembleability. The allowable variation of the matting parts in the assembly of the pin and the ring – both with MMR is also shown in the application Geometrical Tolerancing. The variation of the mating parts surfaces is animated in the Interpretation window (Fig. 9) which is obviously not possible to show by the screen shoots given in the paper. The common maximum material virtual condition envelope that secures assembly without interference should not be violated by the actual pin surface from inside and the actual hole surface from the outside.

whether the user fully understands the major concepts of particular geometrical tolerances which were initially explained in the specification windows. The application Geometrical Tolerancing is created with powerful multimedia creation tool Adobe Flash CS5 and might be run in off-line and on-line modes. It may be executed on any PC as the separate package, as it is performed now during lectures and vocational trainings in industry, or can be embed on the web page and used for the distance learning by any web browser, as it is intended to be implemented.

3. Conclusions

Acknowledgements

We decided to develop the application Geometrical Tolerancing because, the proper understanding of the requirements specified in the technical product documentation is a key issue to correct communication between the designers, manufacturing and metrology engineers, especially in the case of companies that deliver or outsource parts. This paper presents the general structure and capability of the application and contains only a small sample of the over 200 windows that user can click through to become familiar with the geometrical tolerancing concepts. The interactive animations help students and young engineers to understand the rules of the geometrical tolerancing given the ISO standards. An experienced engineer can also clarify and improve the knowledge about the tolerancing. Currently the course is based on the definitions and rules presented in the series of the ISO GPS standards, however some highlights on the ASME Y14.5 standard will be added. Due to the interactive animations enriched by the questions addressed in the test boxes the user has opportunity to control step by step the graphical assessment of the geometrical deviations on the actual parts. Such option is exceptionally effective to verify

The authors wish to express gratitude to Prof. S. Zebrowska-Lucyk from Institute of Metrology and Biomedical Engineering, WUT, for her valuable remarks and support during development of the pre-beta version of this application.

References [1] Humienny Z. State of Art in Standardization in GPS Area. CIRP Journal of Manufacturing Science and Technology, 2009; v.2, p. 1–7. [2] Dantan J-Y, Ballu A, Mathieu L. Geometrical product specifications — model for product life cycle. Computer-Aided Design, 2008, v. 40(4), p. 493-501. [3] www.ifgps.com; access December 2012. [4] www.etinews.com; access December 2012. [5] www.symphonytech.com/gdtwiz.htm; access December 2012 [6] Maropoulos P.G, Ceglarek D. Design verification and validation in product lifecycle. CIRP Annals - Manufacturing Technology, 2010, v. 59(2), p. 740-749. [7] Humienny Z, Bonarowski J, Stanczuk R, Urbaniak P, Wojtczak K. New multimedia training course in geometrical tolerancing. 9th International Symposium on Measurement and Quality Control (9th ISMQC), 2007, IIT Madras. ..